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About the Authors:
Li Lin
Affiliations USDA-ARS, Plant Genetics Research Unit, Donald Danforth Plant Sciences Center, Saint Louis, Missouri, United States of America, Department of Agronomy, University of Wisconsin, Wisconsin, United States of America
Shulan Tian
Affiliations USDA-ARS, Plant Genetics Research Unit, Donald Danforth Plant Sciences Center, Saint Louis, Missouri, United States of America, Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin, United States of America
Shawn Kaeppler
Affiliation: Department of Agronomy, University of Wisconsin, Wisconsin, United States of America
Zongrang Liu
Affiliation: USDA-ARS, Appalachian Fruit Research Station, Kearneysville, West Virginia, United States of America
Yong-Qiang (Charles) An
* E-mail: [email protected]
Affiliation: USDA-ARS, Plant Genetics Research Unit, Donald Danforth Plant Sciences Center, Saint Louis, Missouri, United States of America
Introduction
Seed germination is a biological process important to plant development, plant evolution and agricultural production. Strictly defined, germination begins with the uptake of water by dry quiescent seeds and ends with visible emergence of an embryo tissue from its surrounding tissues [1]. Seed germination is accompanied by many distinct metabolic, cellular and physiological changes. For example, upon imbibition, the dry quiescent seeds take up water and rapidly resume many fundamental metabolic activities such as respiration, RNA metabolism, and protein synthesis using surviving structures and components in the desiccated cells. These concerted biological activities transform a dehydrated and resting embryo with almost undetectable metabolism into one with vigorous metabolism culminating in growth [2], [3].
Transcriptional regulatory program underlying seed germination and its associated biological pathways were investigated in divergent plant species [4], [5], [6], [7], [8], [9], [10], [11]. Extremely complex transcriptional regulatory programs are activated over the course of seed germination. In barley germination and seedling growth, 50% of examined genes are expressed in dry and germinating seeds at a detectable level. Twenty-five percent of those examined genes are differentially regulated over the course of seed germination and seedling growth. Based on global and dynamic expression changes of the germination-regulated genes, the transcriptional regulatory program underlying barley seed germination is divided into early and late phases. Each phase is accompanied by differential expression of a distinct set of genes and biological pathways. For example, the early phase of seed germination is accompanied by transcriptional up-regulation of cell wall synthesis and regulatory components including transcription...